- Diethylzinc: A simple and efficient catalyst for the swift hydroamination at room temperature
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Diethylzinc and dimethylanilinium tetrakis(pentafluorophenyl)borate were found to catalyze hydroaminations at room temperature in high efficiency and very short reaction times. The reactivity of the proposed cationic zinc species, which is assumed to cata
- Pissarek, Jens-Wolfgang,Schlesiger, David,Roesky, Peter W.,Blechert, Siegfried
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scheme or table
p. 2081 - 2085
(2009/12/28)
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- Nonracemic betti base as a new chiral auxiliary: Application to total syntheses of enantiopure (2S,6R)-dihydropinidine and (2S,6R)-isosolenopsins
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(Chemical Equation Presented) Total syntheses of enantiopure alkaloidal natural products (2S,6R)-dihydropinidine (as hydrochloride) and (2S,6R)-isosolenopsins (as hydrochlorides) were achieved in four steps and in 80-82% total yields by using a synthetic strategy of the formation-cleavage of 1,3-oxazinane. (S)-Betti base was proved to be an excellent chiral auxiliary and a novel Pd/C catalyzed N-debenzylation straightforward to amine hydrochloride was developed in the presence of CH2Cl2.
- Wang, Xinyan,Dong, Yanmei,Sun, Jianwei,Xu, Xuenong,Li, Rui,Hu, Yuefei
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p. 1897 - 1900
(2007/10/03)
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- METHOD FOR SYNTHESISING OPTICALLY ACTIVE PIPERIDINES BY THE HYDROGENATION OF OPTICALLY ACTIVE PYRIDINES
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The invention relates to a method for preparing optically active piperidines by the hydrogenation of pyridines using a suitable catalyst. Said method enables the preparation of a plurality of piperidine derivatives with high optical purity and in high yields.
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Page/Page column 15
(2010/02/12)
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- A simple stereoselective synthesis of enantiopure 2-substituted pyrrolidines and piperidines from chiral (R)-phenylglycinol-derived bicyclic 1,3-oxazolidines
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Chiral, nonracemic 2-substituted pyrrolidines and piperidines were prepared in high ee and moderate to good chemical yields in three steps from (R)-phenylglycinol and γ- or δ-chloroketones. The key step of the synthesis was the stereo- selective reductive ring-opening of chiral bicyclic 1,3- oxazolidines prepared by condensation of (R)-phenylglycinol and the corresponding ketones.
- Andres, Jose M.,Herraiz-Sierra, Ignacio,Pedrosa, Rafael,Perez-Encabo, Alfonso
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p. 1719 - 1726
(2007/10/03)
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- Facile diastereoselective reactions of chiral 1,3-oxazolidines with grignard reagents; asymmetric syntheses of 2-substituted and 2,6-disubstituted piperidines
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(S)- and (R)-2-Phenylpiperidines, (S)- and (R)-2-methylpiperidines, meso- and (2R, 6R)-2,6-diphenylpiperidines, and meso- and (25, 65)-2,6-dimethylpiperidines were synthesized asymmetrically starting from the diastereoselective addition of Grignard reagents to chiral 1,3-oxazolidines, converting of 1-aza-4-oxabicyclo[4.3.0]nonane derivatives as pivotal intermediates.
- Poerwono, Hadi,Higashiyama, Kimio,Yamauchi, Takayasu,Takahashi, Hiroshi
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p. 385 - 400
(2007/10/03)
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- Asymmetric Electrophilic α-Amidoalkylation - 10: A new Camphorimide Derived Chiral Auxiliary for the Asymmetric Synthesis with N-Acyliminium Ions - Preparation of Aracemic 2-Substituted Piperidines
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Compound 5 is a new α-amidoalkylation reagent for the asymmetric synthesis of 2-substituted piperidines.Its chiral auxiliary 3 is derived from camphoric acid and designed for an asymmetric induction mechanism featuring precomplexation as the decisive step
- Wanner, Klaus Th.,Paintner, Franz F.
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p. 3113 - 3122
(2007/10/02)
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- Synthesis of azetidine, pyrrolidines and piperidine by intramolecular cyclization of ω-Azidoboranes.
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This paper describes the development of efficient routes to azetidine, pyrrolidines and piperidines by creation of a carbon-nitrogen bond.Two complementary syntheses of these heterocycles were studied : the cyclization of ω-azidoboronic esters by treatment with boron trichloride, and the one pot hydroboration of an ω-azidoalkene and intramolecular reductive alkylation.The scope and limitations of these two promising approaches are reported.Keywords: azides / boronic esters / boranes / intermolecular cyclization / azetidine / pyrrolidine / piperidine / pyrrolizidine
- Jego, J. M.,Carboni, B.,Vaultier, M.
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p. 554 - 565
(2007/10/02)
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- Synthesis of Pyrrolidines and Piperidines via Intramolecular Cyclisation of ω-Azidoalkyl Boronic Esters
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Intramolecular cyclisation of ω-azidoalkyl boronic esters occurs in the presence of boron trichloride and leads, after hydrolysis, to the corresponding pyrrolidines or piperidines.
- Jego, Jean Michel,Carboni, Bertrand,Vaultier, Michel,Carrie, Robert
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p. 142 - 143
(2007/10/02)
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- 3,6-Bis-(heterocyclic aminoacyl-amino)-acridines and salts thereof
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Compounds of the formula STR1 wherein R1 is hydrogen or methyl, R2 and R3, together with each other and the nitrogen atom to which they are attached, form a saturated or unsaturated heterocyclic ring system which may optionally contain one or more additional heteroatoms, and A is lower alkylene or aryl-lower alkylene, and nontoxic, pharmacologically acceptable acid addition salts thereof; the compounds as well as their salts are useful as inducers of the formation of interferon.
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